Improvement in heating-stoves



,I.`G. MACFARLANE.

, H'atifhg -S toyes. i

No 145 744, y Pgfented'uec. 23,1973,

NITED STATES PATENT OFFICE.'

ISAIAH MACFARLANE, OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT IN HEATING-STOVES.

Specification forming part of Letters Patent No. 145,744, dated December 23, 1873; application filed September 23, 1873.

To all whom 'it may concern:

Be it known that I, IsAIAH G. MACFARLANE, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Stoves; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawing, forming a part of this specication, in which- Figure 1 is a perspective view of my improved stove. Fig. 2 is a vertical section. Figs. 3, 4, and 5 are, respectively, sections through A A, B B, and@ C, Fig. 2; and Fig.

6 is a vert-ical section of the base.

My improvement is designed to effect the combustion of smoke and gases,which escape unconsumed from. the fire-chamber of stoves in which bituminous coal and other fuel rich in carbon are used.v .In the stove to which I have applied my improvements there are two grates, arranged, one over the other, in such a manner that the draft from the lower one shall be directly through the upper one, and so near each other that the heat radiated down from the upper grate shall operate upon and aid in the combustion -of the fuel in the lower one. In this stove bituminous coal and other fuel rich in carbon and hydrogen are used on the lower grate, and on the upper grate anthracite coal, coke, or other ,fuels which contain little, if any, volatile combustible matter.

My improvement consists, rst, in the construction of the upper grate, which is made of fire-clay or other like material, with suitable lues for supplying the requisite amount of oxygen to the center of the ascending current of combustible gases from the lower fire. It also consists of alseries of openings for admitting oxygen into the lower chamber of the stove, just below the upper grate, such oxygen mingling with the other portion of the ascending current, to supply sufcient oxygen at that point.

To enable others skilled in the art to make and use my improvement, I will vdescribe its construction and manner of use.

The stove a is of the usual cylindrical shape, and is provided with a grate, b, of the ordinary construction, at or near the base. At or near the middle of the stove is a second grate, c, which is made of fire-clay or other like infusible material. This grate has a series of flues, c1, leading in from the outer casing to the cen ter openings c2, for the purpose of supplying air at that point. Opening into the chamber l are a number of ports, g, which admit air around the sides of the stove. The chamber d is tted with a door, 7L, by means of which fuel is supplied, Snc., and the chamber e has a similar door, c'. At the top of the stove is a heat-radiating drum, f, which projects over the sides of the stove into the path of the current of air, which, heated' by the hot sides of the stove, ascends around it. In this projecting edge I make a series of vertical iiues, k, through which the ascending heated air passes. The heat on the inside of the stove circulates around these tubes, sovas to heat them very highly, such heat being transmitted through them and given ott' into the ascending currents of air. Attached to the drum is a smoke-pipe, a. The base l is fitted with an ash-pan, on, in the usual way. Hung to the links p is a vibrating stirrer, q, the bars of which stand across the wide portions of the openings 1'. The distance between the bars of the stirrer and the sides of the wider portions of the openings r, is equal to the distance between the bars of an ordinary grate. The ends r' of the openings 1^ which are beyond the ends of the bars of the stirrer, are narrower, so as to be about equal to the space beA tween the bars of an ordinary grate. WVhen it is desired to stir the flre in the grate b, the stirrer q is moved, by means of the handle q', backward and forward, thereby communicating to it an oscillating movement upon the links p. In this movement the bars of the stirrers swing into and from the narrow ends ofthe openings r, rising at the ends and fallin g in the center. This movement is similar to the movement of a poker in a grate of the or dinary construction.

The operation of this stove is asfollows: The re is first made inthe upper grate c, of coke or other like fuel, andwhen the draft is fully established a fire of bituminous coal is made upon the lower grate b. Then the as cending smoke and gases from the lower grate are drawn through the upper fire and there consumed. The oxygen necessary to the consumption of these gases is supplied, irst,

through the openings g, around the edges of the ascending current, and, second, through the iiues 01 a-nd center openings c, to the center of the ascending current. Some of the gases which are generated in the lower chamber are not consumed by being simply passed through a re of incandescent coals, like the Ire in the grate c, but are changed in formthat is, are rendered invisible. This fact has often given rise to the erroneous impression that these gases are consumed, thus explaining the reason of the failure of many smokeconsuming apparatus. If, however, sufficient oxygen is supplied under suitable conditionsthat is, in the presence of intense heatthese gases are combined therewith and consumed. Some combine with the oxygen of the air, so as to be consumed, in the ratio of eighteen part-s, by weight, of air to one part of gas. In order that the oxygen maybe intimately intermixed with these gases, I have made two sets of air-fines, g and c1, so as to reach all portions of the ascending gaseous current. rIhe fire on the upper grate not only consumes the gases from below, but, becoming intensely heated on account of the extremely combustible nature of the gaseous fuel, radiates heat down upon the lower lire, so as to aid in the combustion of the fuel thereon. This causes a very rapid generation of the gases from the lower iire. After the fire on the upper grate has once been kindled, it does not require to be renewed more than once or twice a day, because the volatile fuel from the lower fire, supplying' food for combustion, causes it to operate much in the same way as the wick in a candle. By

this arrangement I am enabled to use very inferior fuel in the lower grate.

The iire in the lower grate is designed not only for heating purposes, but also for generating volatile fuelfor the upper grate. The upper grate-fire requires, as beforesaid, but little attention, and consequently but little labor in removing ashes, Src., thus rendering the stove, with the exception of the work at the time of kindling the tire therein, of no more additional trouble than an ordinary stove.

The advantage of this stove, in addition to its utility in, affording a convenient and easy method of utilizing and saving fuel, by the consumption of the smoke and gases, is its great heating power. rIlhe reason I form the grate c of an infusible indestructible material is because of its exposure to the heat of the two iires. If made of metal it would be burned out in a short time. The ports g and ilues cl may be fitted with dampers, consisting of fiat metallic rings extending around the stove, susceptible of a slight movement, and having openings to register with the ports and iiues.

Vhat I claim as my invention, and desire to secure by Letters Patent, is-

l. The grate o, constructed of fire-clay or other infusible material, havin g liues ol extending to the center openings c2, substantially as and for the purposes described.

2. The grate c, having iiues c1, in combination with the fire-chamber d, having' ports g, and a grate, b, substantially as described.

In testimony whereof I, the said IsArAH G. MAGFARLANE, have hereunto set my hand.

ISAIAII G. lVIACFARLANE.

`Witnesses T. B. Kanu, JAMES I. KAY. 

